I think you might be surprised. I'm an avid koi (carp) keeper. Our hobby is very much rooted in Japan because that's where serious koi carp breeding began and where the knowledge and the understanding exists.

As such, there is a world wide respect for the skills of Japanese breeders and many of the books written by them in Japanese have been translated into English and have good sales figures. The pictures in these books are spectacular and go a long way towards educating English speaking Westerners in the art of choosing our purchases carefully and knowledgeably so that, we too, can grow koi carp to 80+ cm and which, throughout their lives, still exhibit the qualities that we look for.

I've passed on the translation and my friend will now be looking for a translated edition.